Paper making



Patented Oct. 1933 UNITED ST T S 1,959,205 rarna MAKING Clarence EarlLibby, Syracuse, N. Y., m... a National Aluminate Corporation, Chicago,111., a corporation of Delaware The present invention relates to animproved process for the manufacture of paper, cardboard. pulp-board andthe like, having special reference to the sizing and web-forming steps.

One 'of the major objects of the invention is to improve the efliciencyof the sizing operation, as well as'to diminish the amounts ofsizingreagents required to bring a given type of paper to apredetermined degree of size resistance.

A further object of the invention is to treat cellulosic fibers that aresuspended in water in a beater with a water-soluble aluminate for thepurpose of neutralizing the water to a point where ,the size, whensubsequently added, will be more 15 efliciently dispersed so that, whenit is later precipgliizted upon the fiber by the addition of the u lprecipitants, such as aluminum sulphate, a much more thorough sizing ofthe fibers will result. A secondary, but. valuable, result is '20obtained by the use of the aluminate" in that the resulting sized stockis considerably freer, so that the speed of web production can beconsiderably increased, w ile there will also beless loss of fiber inthe wh e-water. 1

Other objects will become apparent as the invention is furtherdescribed.

The invention therefore may be summed up asconsisting of the process ofimproving the sizing operation in paper manufacture by the ada justmentof the acidity or hydrogen ion concentration of the vz'ater in thebeater to about the point of neutrai ty (pH 7.0) by means of a solublealuminate, followed by addition of the size and, later, by the usualaluminum sulphate. Ex-

act neutrality need not be attained, the useful range being between pH5.0 to pH 8.0.

In this connection it should be understood that the action of the sodiumaluminate is not one of mere neutralization, for, as will be shown in 40detail hereinbelow, the effects obtained can not be interpreted merelyupon the alkalinity of the sodium aluminate.

Paper is sized for the purpose of making it resistant to the penetrationof water, ink, oil, or

' other fluids. Ordinarily, sizing is accomplished by introducing intothe paper sheet a water resistant material such as rosin, glue, casein,or paramn wax. Rosin is the most common and eificient sizing materialand is used in far greater 5 quantities for this purpose (than all othermaterials combined.

Rosin itself is not soluble in water but is brought into a soluble stateby treatment with an alkali, the solution being accomplished either withor without the application of heat. The re- Drawing. Application span,1932 Serial No. 603,223

suiting thick rosin soap", so called, may be added directly to the paperpulp beaters but is more commonly emulsified" or diluted with water to aconcentration of 2% to 5% before it is added to the pulp stock. Afterthe addition of the rosin emulsion, the size is usually set or fixed onthe fibers by the addition of aluminum sulphate,

or paper makers alum, although in special cases the alum is added beforethe rosin size.

Notwithstanding the apparent simplicity of this operation, the practicalresults obtained are often quite variable and sometimes sounsatisfactory that the finished paper cannot be utilized for theintended purpose. It is possible to add the proper amount of size andalum in the correct manner and produce no increase in the sizeresistance of the paper over the unsized pulp, i. e., the

efficiency of the operation has been zero. While this result would seemunusual, it is not unusual, and in fact it is common for the sizeresistance of a given sheet manufactured in a single mill to vary insize resistance from run to run, from day to day, and even, in somecases, from hour to hour as much as several hundred percent.

I have found that the greatest cause of this fluctuation in sizeresistance is due to a varying acidity of the pulp suspension in thebeater. The dispersion of the colloidal rosin size suspension isaffected by this acid condition at the moment of addition to the beater,and the resulting size resistance of the paper manufactured from thispulp is a function of the dispersion of this size. Other factors beingconstant and within well defined limits, the greater the acidity of thepulp at the time of addition of the size, the less will be the sizeresistance of the manufactured paper. The variation in acidity of thepulp beaters is due to a number of factors, chief among which may bementioned residual acid from the liquors in which the wood was cooked,acid from the bleaching operation, free acid from the alum and mineralfiller which has accumulated in the white water, this water ordinarilybeing reused for dilution in the heaters, and acid resulting from thetrue hydrolysis of the alumi- 1-11 num sulphate.

The process which I have developed for the use of sodium aluminate inconnection with the sizing operation depends in part on the power of thealuminate to-neutralize the pulp stock acidity its; and thereby createmore favorable conditions for the dispersion of the rosin size emulsion.

In practice the pulp'suspension in the beater will have an acidity,expressed in terms of pH units, ranging from pH 3.5 to pH 8.5, dependingllo upon the combination of factors enumerated heretofore and uponwhether ,the pulp stock was prepared by an acid or an alkaline process.If the pulp was prepared by an acid process, or has been subjected to ableaching treatment, or is suspended in the white water which drainsaway from the paper machine wires, it will have, ordinarily, an aciditynot greater than pH 6.0 and probably not greater than pH 5.0. It is myprocess to adjust this acidity to approximate neutrality (pH 71)) by theaddition of sodium aluminate, although in special cases the adjustedacidity varies from pH 5.0 to pH 8.0. The rosin size emulsion is thenadded and after thorough id agitation the mixture of rosin and-aluminateis precipitated throughout the pulp stock by the addition of suificientaluminum sulphate or other acid salt to adjust the acidity back to pH4.0 or whatever figure has been determined to givefiii maximum sizingresults.

The' use of sodium aluminate for this purpose is originai with me andgives results which cannot obtained with any other alkaline salt,theselresuits being due in part to the neutralizing 2d" powers)? thealuminate and in part to the colloidal fioc resulting from theinteraction of the aluminate and the residual acid or aluminumsulphatedissolved in the water of the pulp suspension. This iloc being of itselfa colloid serves to disperse the rosin size emulsion and greatly assistsin the even distribution and uniform sizing ofthe'i entire paper she'etjf It is also evident that the presence of the aluminate causes a morecomplete precipitation of the rosin size, which brings abouta greaterretention of rosin size in the sheet and results in less loss of sizeand alum in the machine white waters. This enables amill to greatlyreduce the amount of rosin size addition to obtain a given degree of 40sizing or size resistance in their paper and results in significanteconomies in the manufacturing process. If a mill is unable tomanufacture a satisfactorily sized paper without aluminate, M theaddition of this chemical will increase the 46 degree of sizing'in theirproduct to a satisfactory value and thereby enable the milktomanufacture more salable merchandise.

In addition to the aforementioned benefits: the flocculating power ofthealuminate added to. the E beater causes an agglomeration of the finefibers in the pulp suspension, ,these fine fibers being trapped by thealuminatefioc and the whole mass enmeshed in the fiber structure of thepaper I sheet in a manner which prevents these fine fibers 53" frompassing through the fiber'mat of the wet paper sheet on the machine wired subsequentlythroughthe machine wire 1 1f, resulting. in amarkeddecrease in the loss of fine fibers in the white water effluent-going tothe sewers. 66 "Furthermore, the addition of sodlum aluminote to anypaper pulp stock gives in some cases a soft flexible paper sheet similarto'a wood fiber .prepared'by the soda chemical pulping process A p andhighly desirable for the manufacture of 66 bo'okpapers. By closelyregulating the initial and final conditions of acidity, together withthe time or treatmentin the boaters, exactly. the opposite effect may beproduced, at will, and a F stiff strong paper sheet similar incharacteristics .'0-- to a rag paper-sheet, may be manufactured from oroth'er fibers of inferior initialstreng'th and less economic valuethan'the-rag'fibers which 'Th'eaddltidn of aluminate' to .the pulp stockin thebeaters, or at any other point in the'line be the case.

(b) It permits the fibers to form or felt. more quickly on the papermachine wire and results in a more dense, uniform, and finely knit sheetknown to the paper makers as a sheet with closed" formation.

(0) It enables the felts, suction boxes, and

presses of the paper machine to remove with less difiiculty thesuspension water associated with the fibers and permits the papermachine to be operated at decidedly greater speeds.

(d) It enables the paper machine dryers to evaporate the residual waterin the wet sheet leaving the presses with a smaller amount of steam,resulting in decreased drying costs and also permitting greateroperating speeds, as the speed of the operation of a paper machine isoften determined by its drying capacity.

(e) It largely negatives the tendency of hydrated pulp stock to shrinkas it drys on the-rotating steam-heated drying drums of the papermachine and permits a machine to manufacture a sheet of greater widththanwould be possible without the use of sodium aluminate. I

. The results of tests made on an operating scale, using sodiumaluminate in the heaters, with the object of increasing the efiiciencyof the sizing operation, will now be described. I

These tests were made during a regular run of 16 point board, and, as aprevious test had indicated that a substantial increase in the size testresults from the addition of aluminate, an immediate cut of 25% in boththe size and alum furnish was made simultaneously with the addition ofaluminate. The size and alum furnish per beater during this test was asfollows:

Alumisim nate at 46 lbs.

Ply Alum 50 lbs. 55 lbs.

4 lbs.

a; liner p 4 lbs.

Bottom liner out of 25% in both size and alum f 30 sec.

2. Size test on board manufact with a cut of 25% in th size and alum f hbut with 41%. solid sodium aluminate l8 min. 18 sec. a

'. 3. Size test on board manufac ured with a s h, but with 4 lbs.ofrliquid sodium aluminate, (based on A120: content) in each linerbeater-7 min. 54 sec.

An inspection of the foregoing tests indicates that a marked increase insizing accompanies the ;45

use of solid sodium aluminate but that the liqui aluminate is not quiteso effective, although the present standard test was practicallymaintained a with this product even after a 25% cut in size and alum. vC

in each liner beater I v per, three runs were made, one usingordinaryfresh lake water having an initial hydrogen-ion concentration ofpH 6.4,,and when treated with the alum used for the precipitation, of pH4.2. The size test in this case was 106 seconds. A second run was thenmade with the use of the white-water from the first run in the heaters,so that the water in the beater had an initial hydrogen-ion.concentration of pH 4.2 both before and after addition of the necessarypaper-markers alum to effect the precipitation. The size test in thiscase was only 80.1 seconds. a

A third run was then made, employing the white-water from run No. 2,which had an initial hydrogen-ion concentration ofpH 4.2. Sufficientsodium aluminate was then added to bring the hydrogenion concentrationof the water in the beater to the neutral point, i. e., pH 7.0.Thereupon the regular amount of size was added and the size precipitatedby means of alum, in 'ex-' actly the way it had been done with the twopreceding runs. The size test on the resulting paper was 277.4 seconds,or an increase over run No. 2 of 246%. It is thus plainly'evident thatthe addition of the aluminate very greatly increased the size resistanceof the paper.

In order to obtain still more convincing proof of the remarkable effectobtained when practicing the present invention, a number of further testruns were made. These were as follows:

Run No. 4.-A run made for the purpose of preparing white water andemploying aiurnish' of fresh water, rosin size, sodium aluminate andalum. Run No. 5.--A run made for the purpose of preparing white waterand employing a furnish of white water from Run No. 4, rosin size,sodium aluminate and alum.

Run No.1 6.A run made for the purpose ofdetermining the specific effectof sodium aluminate on the efllciency of the rosin'sizin'g operation andemploying a furnish of white water from Run No. 5, rosin size, sodiumaluminate and alum.

In order to prove that the effect obtained could not be ascribed merelyto the neutralization of the white-water used in the beater, threefurther test runs were made, using sodium carbonate as the neutralizingmedium. These were as follows:

Run No. 7.-A run made for the purpose of preparing white water andemploying a furnish of fresh water, rosin size, sodium carbonate andalum.

Run No. 8.-A run made for the purpose of preparing whitewater andemploying a furnish of white water from run No. 7, rosin size, sodiumcarbonate and alum. v

Ru'n No. 9.A run made for the purpose of determining the specific effect'of carboriate on the efficiency of the rosin sizing operation andemploying a furnish -of white water from Run No. 8, rosin size, sodiumcarbonate and alum. I r

The details of these runs are as follows:

v I I Run No.4 v

Pulp-100% Dexter bleached mitscherlich sulphite pulp. v

Pulp furnish-10 lbs. air dry at consistency. Beating time-Two hours.fifteen minutes.

. Beater roll setting-3s on Bristol recorder.-

' 'ity of the pulp inthe beater to a pH of 4.2.

Alirminhte-Dissolved C. P. sodium alumina {e added after fifteen minutesof beating sufllcient quantity to increase the pH of the pulp suspensionin the beater to a pH of 7.0 rosin size then added to the beater.Aluminate furnish-The equivalent of 4.4 lbs. of dry C. P. sodiumaluminate per ton of air dry pulp. I Alum-Dissolved C. P. aluminumsulphate add-L ed after one hour fifty-five minutes of beatinginsufficient quantity to adjust the acidity of the pulp in the beater toa pH of 4.2. Alum furnishThe equivalent of 88.2 lbs. of C. P. aluminumsulphate per ton of air dry pulp. Green's freeness testNone. TestsheetsP-None.

Valley size test-None.

Run N0. 5

, Pulp- 100% Dexter bleached mitscherlich sulp i em n Pulp furnishlbs.air dry at 5% consistency. Beating time-Two hours, fifteen minutes.Beater roll setting-38 on Bristol recorder. Water-' White water fromRunNo. 4, having aninitial pH of 4.2. Rosin size-Paper Makers'ChemicalCorp.,

solids, 18% free rosin. Rosin size furnish-5% of 60% size, or 3% rosinon air dry weight of pulp. Aluminate-Dissolved C. P. sodium aluminateadded after fifteen minutes of beating -and in sufllc'ient quantityltoincrease the pH of the pulp suspension in the beater from pH 4.2 to a pHof- 7.0. Rosin size then added to the beater. I

Aluminate furnishThe equivalent of 18.7 lbs. of dry C. P. sodiumaluminate per ton of air dry pulp.

Alum-Dissolved C. P. aluminum sulphate added after one hour fiftyminutes of beating and in sufficient quantity to adjust the acid- Alumfumish--The equivalent of 88.2 lbs. of

C. P. aluminum sulphate per ton of air dry Green's freeness test-None;

Test sheets-None.

- Valley size test-None.

Run No. 6

Pulp-100% Dexter bleached mitscherlich sulphite pulp. Pulp furnish-l0lbs. air at 5% consistency. Beating time-Two hours, 'fifteen minutes.Beater roll setting-38 on Bristol recorder.

waterwhite water from Run No. 5, having .an initial pH of 4.2. Rosinsize-Paper Makers Chemical Corp.,

60% solids, 18% free rosin. Rosin size fumish5% of 60% size, or 3% mainon the air dry weight of pulp.

added after fifteen minutes of beating in sufflcient quantitfto increasethe pH of the pulp suspension in the beater to a'pH of 7.0.'Rosinsizethenadd tothebeater.

1.4-? Aluminate-Dissolved C." P. sodium .aluminate Aluminate furnish-Theequivalent or 18.7 lbs. of C. P. sodium aluminate per ton of air drypulp.

Alum-Dissolved C. P. aluminum sulphate added after one hour fifty-fiveminutes of beating in sufllcient quantity to adjust the acidity of thepulp in the heater to a pH 01. 4.2.

Alum furnish-The equivalent of 88.2 lbs. 0! C. P. aluminum sulphate perton of air dry pulp.

Greens freeness test-None.

Test sheetsFormed on Bureau of Standards sheet machine and air dried at70 F.

Test sheet weights-29.1 grams for 4 sheets Valley size test dataobtained at 70 F. and 65% relative humidity.

. Seconds sample 1 180 Sample 2 182 Sample 3 191 Sample 4 148 Sample 5190 Sample 6 162 Sample '7 196 Sample 8 205 Sample 9 145 Sample 10 165Average 176.4

Run N0. 7

Pulp-100% Dexter bleached mitcherlich sulphite pulp.

Pulp furnish-10 lbs. air dry at 5% consistency.

Beatingtime-Two hours, fifteen minutes.

Beater roll setting-38 on Bristol recorder.

Water-Fresh water having a pH of 6.4.

Rosin size-Paper Makers Chemical Corp.,

60% solids, 18% free rosin.

Rosin size furnish-5% of 60% size or 3% rosin on the air dry weight ofpulp.

Aluminate-Nona Soda ash-Dissolved C. P. sodium carbonate added afterfifteen minutes of beating and in suiiicientquantity to increase the 'pHof the pulp suspension in the beater from 6.4 to a pH of 7.0. Rosin sizethen added to the beater.

Soda ash fumish-The equivalent of 2.2 lbs. oi. CJP." sodium carbonateper ton of airy dry pu1p Alum-Dissolved C. P. aluminum sulphate addedafter one hour fifty-five minutes of beating and in suflicient quantityto adjust the acidity of the pulp in the beater to a pH of 4.2. Alumi'urnish--The equivalent of 88.2 lbs.'o1

pulp. Green's freeness test-None.

meaeoe Soda ash-Dissolved 3?. sodium carbonate added after fifteenminutes of beating and in suficient quantity to increase the pH of thepulp suspension in the beater from 4.2 to a pH of 7.0. Rosin size thenadded to the beater.

Soda ash furnish-The equivalent of 8.9 lbs.

I Green's freeness test-None.

Test sheetsNone. Valley size testNone.

Run No. 9

Pulp% Dexter bleached mitscherlich suiphite pulp.

Pulp furnish-10 lbs. air dry at 5% consistency.

Beating timeTwo hours, fifteen minutes.

Beater roll setting-38 on Bristol recorder.

Water-White water from Run No. 8, having an initial pH of 4.2.

Rosin size-Paper Makers Chemical Corp.,

60% solids, 13% free rosin.

Rosin size furnish-5% of 60% size, or 3% rosin on the air dry weight ofpulp.

AIuminate-None.

Soda ash-Dissolved C. P. sodium carbonate added after fifteen minutes ofbeating and in sufiicient quantity to increase the pH of the pulpsuspension in the beater from 4.2 to a pH of 7.0. Rosin size then addedto the heater.

Soda ash furnishThe equivalent of 8.9 lbs. of -C. P. sodium carbonateper ton of air dry "pulp.

Alum-Dissolved C. P. aluminum sulphate added after one hour fifty-fiveminutes of beating and in sufficient quantity toadjust the acidity ofthe pulp in the beater to a pH of 4.2.

- Alum fumish-The equivalent of 88.2 lbs of C. P. aluminum sulphate perton of air dry pulp.

. Green's ireeness test-None.

Test sheets-Formed on Bureau of Standards sheet machine and air dried at70 F.

Test sheet weights-30.5 grams for 4 sheets Valley size test dataobtained at 70 F. and 65% relative humidity.

Test sheetsNone."' Valley size testNone.

Run N0. 8

Rosin size furnish-5% of 60% size, or 3% rosin on the air dry weight ofpulp. illuminate-None;

- Seconds Sample 1 125 Sample 2 135 Sample 3 120 Sample 4 107 Sample 5118 Sample 6 122 Sample 7 115 Sample 8 134 Sample 9 i 110 Sample 10Averag I 11 1 The procedures followed in making the runs Just describedwere identical with those employed inmalring runs Nos. 1-3. However, itwas decided to make an accurate check on the quantity of aluminate, sodaash, and alum used as well as on the pH obtained, and the data obtainedfrom these measurements are tabulated and discussed in the descriptionto follow.

Owing to the considerable length of time required to complete these sixruns, it was decided to omit the freeness test, as this test is quitetime consuming and as very little variation in freeness could beexpected when such close control was maintained over the beater 'rollsetting and the time allowed for hydration.

It will be quite obvious to those skilled inthis art that the precisesequence of the addition of the materials need not be followed. Forexample, it would be an equivalent to add the aluminate to the waterbefore mixing the fibers therewith; or to add the aluminate to thewater, followed by addition 01' the size, and then to introduce thefibers. A third alternative is to add the fiber and aluminate and sizesimultaneously. In any event, the complete or partial neutralization ofthe water by the aluminate will aid in the proper dispersion of the sizeand in the beneficent results obtained by the use of the presentinvention.

A summary of all '01 the test results obtained is herewith tabulated, soas to bring out most (a) Thatthe neutralization of beater acidity withsodium aluminate prior to the addition of rosin size has a markedbeneficial effect on sizing efllciency.

(b) That the beneficial efiect of sodium aluminate is partially if notwholly due to a more complete precipitation and retention of the rosinsize in the paper sheet and a resulting cleaner white water.

(0) That the neutralization of beater acidity with sodium carbonateprior to the addition of rosin size has an effect somewhat similar .tothat of sodium aluminate, but that the efiiciency of sodium carbonate asa neutralizing agent is apparently only one-third that of sodiumaluminate.

It will thus be seen that the size resistance of paper can be increasedfrom 120 to 277.4% by the use of sodium aluminate for neutralizing thewhite water when the same is used in making up the furnish for thebeaters. When, on the contrary, sodium carbonate is used for a somewhatsimilar purpose, namely, to bring the white water to the neutral pointbefore adding the size, and then precipitating the size by means of theusual papermakers alum (aluminate sulphate),

clearly the advantages of the present invention: the increase insize-resistance is only 49%. It

Efi'ect of the use of sodium aluminate and of sodium carbonate on papersizing Beater water furnish Beater water pH I lg i n Neutralizing aggntn s Size precip. in lbs. ggf increase Nature Source Init. Trted. run 2 3Aluminate q. s 4. 2 7.0 277. 4 248% 4 Aluminate 4.4 6. 4 7. 0 Not run 5Aluminate 18.7 4. 2 7.0 Not run 6 Alumiuate l8 7 4. 2 7.0 176. 4 120% 7Soda ash 2.2. 6.4 7. 0 Not run 8 Soda ash 8.9. 4. 2 7. 0' Not run 9 Sodaash 8.9 4. 2 7. 0 119. 1 49% The foregoing test data explains the reasonwhy the test values obtained for Run No. 3 in the first series of runswere abnormally high due to the fact that the white water for this runhad not had previous treatment with aluminate. As will be noted, thetest values for Run No. 6, which is identical with Run N0. 3 except thatthe white water for Run No. 6 had been treated twice previously withsodium aluminate, shows an increase in sizing value of 120% over Run No.2,

suspended in unneutralized white water. This .test value of 120%corresponds with the test value of 246% obtained for Run No. 3, the runin which the white water had not been treated previously with aluminate.These comparative results furnish positive evidence that the function ofthe aluminate in increasing sizing efficiency is due to its ability tobring about a more complete precipitation and retention of the rosinsize in the paper sheet, thereby clearing the white water of dissolvedsize and alum, and making possible a decidedreduction in size furnish toobtain a given size test value.

The effect of soda ash in increasing sizing efficiency is shown by thesize test value obtained from Run No. 9. These test values indicate adegree of sizing 49% greater than the values from Run No. 2. Thesefigures indicate further that sodium aluminate has approximately threetimes the beneficial effect of soda ash in increasing sizing efiiciency.

The conclusions to be deduced from the foregoing tests are:

will thus be quite apparent that a considerable step has been made inadvancing this particular part of the art of paper making.

Reserving unto himself the benefits of the use of such equivalents aswill occur to the experienced chemist and papermaker, what applicant hasinvented and claims is as follows:

1. The process of sizing cellulosic fibers tor the production of webstherefrom, which comprises treating the fibers in suspension with sizeand a water-soluble alkaline aluminate, and thereupon precipitating thesize upon the fibers by means of an acid-reacting soluble reagent.

2. The process of sizing cellulosic fibers for the production of webstherefrom, which comprises treating the fibers in aqueous suspensionwith sodium aluminate and a size, and thereupon precipitating said sizeupon the fibers by the addition of an alum.

3. The process of sizing cellulosic fibers for the production of webstherefrom, which comprises treating the fibers in aqueous suspensionwith sodium aluminate and a size, and thereupon precipitatintg said sizeupon the fibers by the addition of aluminum sulphate.

4. The process of sizing cellulosic fibers which comprises treating thesame first with a mixture of a rosin sizeand sodium aluminate, andthereupon precipitating both the sodium aluminate and the size by theaddition of aluminum sulphate.

5. The process of sizing cellulosic fibers which comprises treating thesame with a solution or a rosin size and sodium aluminate, and thenacldi salt.

6. The process of increasing the size-resistance or paper which consistsin suspending cellulosic fibers in water that has been neutralized bythe addition of sodium aluminate, adding a rosin size to the suspension,and thereupon acidifying the suspension by the addition thereto of anacidreacting salt.

'1. The process of increasing the size resistance or paper, whic'consists in suspending cellulosic fibers and size in waterthat has beenneutralized with sodium aluminate, and thereupon acidifying theresultant suspension by the addition of aluminum sulphate.

8. In the process of manufacturing paper from cellulosic fibers whichare suspended in the whitee water from a previous run ofpaper-manufacture, the step of neutralizing said white-water by theaddition thereto of suflicient sodium aluminate to bring the suspensionto substantially the neutral point, adding size to the suspension, andprecipitating said size upon the fibers.

9. The process of neutralizing white-water which comprises addingsuflicient sodium aluminate thereto to bring it substantially to theneutral point.-

10. In the manufacture of cellulosic webs the tying the solution bymeans or an acid-reacting improvement which comprises suspending fibersin white-water, neutralizing the suspension with sodium aluminate,adding rosin size to the suspension, adding aluminum sulphate to thesuspension, and thereupon sheeting the fibers. into a coherent web.

11. In the manufacture of webs from fibers, the improvement whichconsists in suspending fibers in an aqueous medium that has ahydrogen-ion concentration above the neutral point, bringing said mediumto substantial neutrality by the addition of sodium aluminate, adding aprecipitable size to the resulting suspension, and then precipitatingsaid size upon the fibers by means of an acid-reacting salt such asaluminum sulphate.

12. The process of enhancing the efiicacy o! rosin sizing of fibers,which comprises neutralizing the water in which the fibers are dispersedby means of sodium aluminate, adding dissolved rosin size, and thereuponadding aluminum sulphate to form an insoluble precipitate of size andaluminum compounds upon the fibers.

13. The process of manufacturing sized paper which comprises preparing amixture of fibers, a soluble aluminate and a sizing-agent, and treatingthis mixture with an acid-reacting size-precipitating agent.

CLARENCE, EARL LIBBY;

